Bicycle frame



FIG. 1 is a perspective view of a bicycle frame;

FIG. 2 is a front view thereof;

FIG. 3 is a back view thereof;

FIG. 4 is a left view thereof;

FIG. 5 is a right view thereof;

FIG. 6 is a top view thereof;

FIG. 7 is a bottom view thereof.

FIG. 8 is a perspective view thereof showing in a position of use, wherein the broken lines showing other positions of a bicycle frame illustrate environmental structure that forms no part of the claimed design; and,

FIG. 9 is a sectional view taken along Line 9—9 in FIG. 4. 

The ornamental design for a bicycle frame, as shown and described. 